Aqueous sprayable compositions can be applied to a hard surface with a transient trigger spray device or an aerosol spray device. These cleaners have great utility because they can be applied by spray to vertical, overhead or inclined surfaces. Spray devices create a spray pattern of the aqueous sprayable compositions that contacts the target hard surfaces. The majority of the sprayable composition comes to reside on the target hard surfaces as large sprayed-on deposits, while a small portion of the sprayable composition may become an airborne aerosol or mist, which consists of small particles comprising the cleaning composition that can remain suspended or dispersed in the atmosphere surrounding the dispersal site for a period of time, such as between about 5 seconds to about 10 minutes. One substantial problem that arises with such spray-on materials relates to an airborne mist or finely divided aerosol generated during the spraying process. The aqueous liquid is converted by the action of propellant or pump action into a spray that is accompanied by a finely divided aerosol or mist. The spray portion contacts and remains on the target surface, while a substantial proportion of the aerosol can remain suspended in the atmosphere.
Such aqueous compositions having a strong base cleaning component in the form of a finely divided aerosol or mist can cause respiratory distress in the user. Upon breathing the finely divided aerosol or mist, a very strong and irrepressible choking response is seen in most individuals that come in contact with irritating proportions of the aerosol produced by typical spray-on cleaners. The choking response is inconvenient, reduces cleaning efficiency in a variety of applications and in sensitive individuals can cause asthma attacks, respiratory damage, or other discomfort or injury.
To alleviate the choking response, some products have been formulated with reduced quantities of the alkaline cleaning components. Strong caustic has been replaced by reduced alkalinity bases such as bicarbonate or by solvent materials. The reduction in concentration or substitution of these materials can often reduce the cleaning activity and effectiveness of the material when used.
Crotty et al., U.S. Pat. No. 3,644,210, teach an alkaline cleaning material useful for removing burnt-on, baked-on food and grease from cooking surfaces comprising substantial proportions of alkali metal hydroxide in an aqueous cleaning base. Eisen, U.S. Pat. No. 3,779,933 teaches an aqueous alkali metal cleaning composition using clay and organic thickening materials. Mukai et al., U.S. Pat. No. 3,813,343, teach oven cleaning compositions containing an amine or ammonia base combined with dimethyl sulfoxide solvent and other compositions. Wise et al., U.S. Pat. No. 3,829,387, teach caustic cleaning compositions containing substantial proportions of sodium hydroxide, clay thickeners, and solvents in an aqueous base. Dillarstone et al., U.S. Pat. No. 4,214,915, and Canadian Patent No. 1,523,491, teach oven cleaning compositions using a relatively mild base such as sodium carbonate and sodium bicarbonate in an aqueous cleaning material. Culshaw, U.S. Pat. No. 4,676,920 teaches a thickened viscous scouring material using surfactants, abrasives and solvents for soil removal. De Buzzaccarini, U.S. Pat. No. 4,767,563, teach liquid scouring cleaning compositions using solvents, abrasives and surfactants for soil removal from hard surfaces. Cockrell, Jr., U.S. Pat. No. 4,877,691 (International Application No. PCT/US91/05092) teaches a barrier coating composition used to pretreat an oven to promote the subsequent removal of hardened baked-on soils that form on the pretreatment material. Dimond et al., Canadian Patent No. 1,047,903, teach oven cleaning compositions having reduced proportions of sodium hydroxide which are thickened using a bentonite in a substantially aqueous base. Silvester, Canadian Patent No. 1,211,674, teaches an improved oven cleaner using sodium bicarbonate as an alkali, glycerol as a solvent, a clay thickener in an aqueous formulation for oven cleaning Flannery, United Kingdom Patent No. 2,019,876, teaches an aerosol comprising sodium bicarbonate as an oven cleaner. Lentsch et al, U.S. Pat. No. 5,364,551 uses xanthan gum as an anti-mist agent in a thickening, Newtonian methodology to increase particle size.
The prior art taken as a whole shows that skilled artisans in experimenting with improving alkaline hard surface cleaners, in particular alkaline oven cleaners, have attempted to reduce concentrations of sodium hydroxide to reduce the choking response. Ammonia or an organic base has been used to replace sodium hydroxide in reduced alkaline cleaners. Other relatively mild inorganic basic materials, such as sodium carbonate or sodium bicarbonate have also been used to replace sodium hydroxide. A variety of organic surfactants or glycol, alkyl ether or dimethyl sulfoxide solvent materials have been used to enhance the detergent properties of the reduced alkaline materials.